A nonstrain-hardening general deformation theory that describes both elastic and inelastic behavior of soils, whether unbound or asphalt-bound, was developed. The theory circumvents the need for yield surfaces or yield stresses separating elastic and inelastic behavior, and it defines elastic plus inelastic behavior as they naturally and simultaneously occur. Soil behavior is unified by the theory being applicable to both cohesive and cohesionless soils. The theory is applicable to soils whether in a pavement structure or beneath a foundation and is applicable for static, moving, and vibratory loadings. Laboratory testing can establish the model and be directly applied to field behavior and vice versa. Soil stress distributions for field loading conditions can be derived from properties and requirements of the theory. Response to moving wheel loads for distributed and mixed traffic on a pavement structure can be completely simulated in laboratory tests based on the theory. Continuation of this research is being sponsored by the Department of Transportation, Transportation Systems Center. (Author).